Solenoid valve systems for controlling flow of hydraulic or pneumatic fluid have been used in automated manufacturing equipment, production lines and numerous industrial applications. A plurality of solenoid valves typically are mounted on a manifold having a plurality of passages for supplying fluid to the valves and providing passages for connecting fluid couplings to various outlet ports of each valve. Each solenoid of each valve typically is separately electrically wired to an electronic system for controlling operation of the several solenoids and valves. The controller may be located at a position remote from the manifold assembly, requiring a multiplicity of extended conductor lengths for individual connection to the valve solenoids.
U.S. Pat. No. 5,522,431 discloses an improved solenoid valve manifold system in which each solenoid is mounted on one side face of a manifold module. The several modules are mounted end-to-end to form a manifold with interconnected through-passages for feeding fluid to and from the several valves. Each manifold module has a terminal block and valve control electronics for hard-wire connection to input/output connectors at the ends of the manifold, and for connection to the associated valve solenoids(s). Although the modular manifold system so disclosed addresses and overcomes problems theretofore extant in the art, further improvements remain desirable. In particular, the manifold system disclosed in the noted patent requires extensive interconnection by hand-wiring, greatly increasing the cost and complexity of manufacture, field installation and repair.
Copending application Ser. No. 08/980,668 filed Dec. 1, 1997, now U.S. Pat. No. 6,053,198, discloses a fluid control system that includes a fluid manifold having a plurality of manifold bodies fastened to each other end-to-end so as to form one or more fluid passages extending through the manifold. A solenoid valve is mounted on a side of at least one of the manifold bodies with fluid ports opening into the manifold body to the fluid passages extending therethrough. An electrical input/output connection is mounted at one end of the manifold for receiving control signals from an external source. A circuitboard arrangement extends within the manifold from the input/output connection and has conductors printed thereon for connecting the input/output connection to the solenoids of the various valves. Each of the manifold bodies includes a passage that extends in assembly through the entire manifold offset from the fluid passages and through which the circuitboard arrangement extends for connection to the various solenoid valves. Both the circuitboard passages and the fluid passages comprise through-passage segments in each of the manifold bodies that align with each other when the bodies are assembled end-to-end to form the manifold. The circuitboard arrangement preferably comprises a plurality of individual circuitboards disposed one within each of the manifold bodies, the various circuitboards being electrically interconnected in series. Each of the circuitboards includes complementary male and female electrical connectors at opposed ends for connecting the boards in series, and a third connector along one lateral side disposed in assembly adjacent to the side of the manifold body on which the solenoid valve is mounted for making electrical connection from the circuitboard to the valve solenoid. This electrical interconnection is made through an opening in the side of the manifold body that is sealed by the electrical interconnection to the valve solenoid. The circuitboards in the preferred embodiments of the invention are provided in two forms, one providing a single output for lateral connection to a single-solenoid valve, and the other providing dual outputs for lateral connection to a dual-solenoid valve. The conductors printed on the circuitboards are arranged such that the output or outputs to the solenoid valve are always taken from the same connection terminal(s) at the upstream connector, with the remaining connector terminals being interconnected in such a way that the control signals for the remaining solenoid valves on the manifold are sequentially presented at the selected terminal(s) of the connectors.
The solenoid valves in this copending application comprise a valve body having a spool for selectively controlling flow of fluid through the valve body from and to the manifold, and from and to the output ports on each manifold body. A solenoid is mounted on one end of the valve body, and has an actuator operatively coupled to the valve spool. A valve control circuitboard is sandwiched between the solenoid and the valve body. The valve circuitboard has a first valve connector for interconnection with the third connector on the circuitboard in the underlying manifold body, and a second connector for connection to the coil of the solenoid in such a way that mounting of the solenoid onto the valve body automatically implements electrical connection to the valve control circuitboard. In implementations in which dual-solenoid valves are employed, with solenoids being mounted on opposed ends of the valve body, a solenoid interconnection extends through the valve body at a position offset from the valve spool for interconnecting the second solenoid with the solenoid control circuitboard. Fluid control means, such as a pressure regulator or a velocity controller, may be mounted between the solenoid valve and the corresponding manifold body side face. Electrical connection between the third connector of the circuitboard within the manifold body and the solenoid control board sandwiched between the solenoid and the valve body is made by a valve interconnection circuitboard that extends through the fluid controller.
It is a general object of the present invention to provide a solenoid valve control system, particularly a solenoid valve assembly, in which the solenoid and the associated control circuitry are provided as a unitary molded or potted assembly. Another and related object of the invention is to provide a solenoid valve assembly that achieves the foregoing objective, and that is characterized by reduced power consumption and reduced operating temperature as compared with the prior art. Yet another object of the present invention is to provide a solenoid valve assembly that includes embedded control circuitry for diagnosing operating condition of the solenoid coil.